The Baylor College of Medicine-UTHouston (Baylor-UTHouston) CFAR Immunology Core is designed to provide both state-of-the-art flow cytometric capabilities as well as expertise and technical assistance for numerous immunological assays desired by members of the CFAR. A major goal is to participate in core initiatives to foster interdisciplinary scientific programs and research in areas of opportunity, including international research and behavioral research. The core is dedicated to providing service in a timely, costeffective, and efficient manner. The core is headed by Dr. Dorothy E. Lewis, who has over 25 years of flow and immunologic experience and a staff of well-trained personnel. The core consists of three flow cytometers, two analytical and a high-speed cell sorter, a BSL2- containment room for immunological assays, and several microscopes. In the previous funding period, the core has been essential for studies involving immune functions and HIV biology and has facilitated interactions with clinical and basic science researchers. In particular, the core was key for studies of Tat kinase activity in primary lymphocytes as well as showing that upregulation in monocytes was necessary for HIV infection, in detection of cytokine messages both in situ and by flow cytometry, in analysis of cell cycle changes driven by viral proteins, and in analysis of lymphocyte activation in viral and parasitic infections. The core has continually developed assays for the users to include a range of services, including flow cytometry, lymphocyte function assays and confocal microscopy. Training on the use of instrumentation and data interpretation is also a key component of the core. The core is supervised by an Oversight Committee. The Core Director has responsibility for day-to-day running of the core;priorities for usage are prescribed in a standardized manner, including an appropriate charge-back system. It is anticipated that at least 25 investigators at Baylor College of Medicine and at The University of Texas- Houston will benefit. These investigators have more than 25 NIH-supported research grants. This core has been highly utilized in our previous funding period as measured by an independent survey and continued support is essential for the success of the Baylor-UTHouston CFAR.